Locating a stoppage in a drainline is normally guesswork, according to Master Plumber and Club member Rex Caldwell of Copper Hill, Virginia. But if you have accessible drainlines, his technique makes finding the obstruction an easy, one-hand operation. First, let all the standing water drain slowly through the clog. Once the water is gone, run very hot water into a bucket, then pour it into the stopped drainpipe until it backs up slightly. Now run your hand along the pipe. Youíll find your stoppage where the pipe turns from hot to cold.